Bug#769616: tasksel: fails to preseed desktop on kfreebsd, hurd

[Steven Chamberlain <steven@pyro.eu.org>]

Package: src:tasksel
Version: 3.29
Severity: important

Hi,

(this bug may also affect linux release architectures other than
i386|amd64|powerpc*, and their CD media, so severity may be higher)

It was seen on kfreebsd and hurd that preseeding with:
  tasksel tasksel/first multiselect standard, desktop
  tasksel tasksel/desktop multiselect xfce
no longer works, a regressions since wheezy;  no desktop gets installed:
https://lists.debian.org/debian-hurd/2014/11/msg00074.html

The logic gets ridiculously complex, but I gather that:

  * tasksel/first item "desktop", used to be the only thing listed;
    selecting or preseeding it would previously install task-desktop
    as well as task-xfce-desktop (whatever was default, or preseeded as
    tasksel/desktop)

  * now, preseeding tasksel/desktop seems to work *only* if
    /usr/lib/tasksel/tests/desktop decides it should install a desktop;
    irrespective of whether tasksel/first includes "desktop"

  * as such, on kfreebsd, hurd and some other arches, selecting or
    preseeding tasksel/first with "desktop" only leads to task-desktop
    being installed (the parent item), but not the individual task for
    desktop, despite setting tasksel/desktop

So I think possible ways to fix this are:

 1. simply adding kfreebsd-* and hurd-* to the list of "common
    desktop architectures" may inadvertently fix this - that determines
    whether tasksel preselects the 'desktop' option by default;
    currently the list has only (linux-) i386|amd64|powerpc* and may
    explain why the bug wasn't noticed there

 2. make tests/default-desktop not conditional on check_desktop_wanted,
    if tasksel/first has "desktop", or tasksel/desktop is preseeded

 3. make tests/desktop (whether to install a desktop) answer "yes"
    (exit 2) if tasksel/first has "desktop", or tasksel/desktop is
    preseeded, overriding any guess it would make based on architecture,
    diskspace, RAM etc. that it does currently

I'll send a patch for consideration that probably does all three in
some way.

-- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'stable')
Architecture: kfreebsd-amd64 (x86_64)

Kernel: kFreeBSD 9.0-2-amd64-xenhvm-ipsec
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash